One of lex luthor's henchman attacks superman, shooting a rapid-fire stream of 3.3 g bullets at him at a rate of 112/min. the speed of each bullet is 527 m/s. because of his super-power, the bullets just stop and fall straight to the ground after striking his chest. what is the magnitude of the average force on superman's chest?

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.